Thermal interface material heat transfer antennas

Abstract

A semiconductor device having a front and a back and comprising a package substrate, an epoxy base layer applied to a back side of the package substrate, and a planar inductor in the epoxy base layer is etched to make a trench at the back of the semiconductor device in the epoxy base layer adjacent the planar inductor, and a thermal interface material is put in the trench, whereby a heat transfer antenna is formed. A semiconductor device has a package substrate having a front and a back; an epoxy base layer applied to a back side of the package substrate, a planar inductor at the back of the package substrate in the epoxy base layer, and a heat transfer antenna at the back of the package substrate in the epoxy base layer.

1 . A method comprising:
 providing a semiconductor device having a front and a back and comprising:
 a package substrate; 
 an epoxy base layer applied to a back side of the package substrate; and 
 a planar inductor in the epoxy base layer; 
   etching a trench at the back of the semiconductor device in the epoxy base layer adjacent the planar inductor; and   forming a heat transfer antenna by putting thermal interface material in the trench.   
     
     
         2 . The method as in  claim 1 , wherein the trench is in the epoxy base layer adjacent the planar inductor. 
     
     
         3 . The method as in  claim 1 , wherein the semiconductor device comprises a die at the back of the semiconductor device and the trench is in the die. 
     
     
         4 . The method as in  claim 3 , wherein the trench extends into the die until just before a doped region of the die. 
     
     
         5 . The method as in  claim 1 , comprising:
 etching a channel at the back of the semiconductor device in the epoxy base layer; and   positioning material to form the planar inductor in the channel.   
     
     
         6 . The method as in  claim 5 , comprising planarizing a back side of the epoxy base layer and material to form the planar inductor. 
     
     
         7 . The method as in  claim 5 , comprising depositing an epoxy cap layer on the back of the semiconductor device, whereby the planar inductor is encapsulated. 
     
     
         8 . The method as in  claim 1 , wherein the planar inductor comprises copper. 
     
     
         9 . The method as in  claim 1 , wherein the semiconductor device has a thickness of 500 μm-700 μm, and the trench has a width of 5 μm-15 μm and a depth of 50 μm-100 μm. 
     
     
         10 . The method as in  claim 1 , comprising putting thermal interface material into the trench with a wiper blade. 
     
     
         11 . The method as in  claim 1 , comprising planarizing thermal interface material in the trench at the back of the semiconductor device. 
     
     
         12 . A device comprising:
 a package substrate having a front and a back;   an epoxy base layer applied to a back side of the package substrate;   a planar inductor at the back of the package substrate in the epoxy base layer; and   a heat transfer antenna at the back of the package substrate in the epoxy base layer.   
     
     
         13 . The device as in  claim 12 , wherein the heat transfer antenna is adjacent the planar inductor. 
     
     
         14 . The device as in  claim 12 , comprising a die at the back of the package substrate and the heat transfer antenna is in the die. 
     
     
         15 . The device as in  claim 14 , wherein the heat transfer antenna extends into the die until just before a doped region of the die. 
     
     
         16 . The device as in  claim 12 , comprising a redistribution layer applied to a front side of the package substrate. 
     
     
         17 . The device as in  claim 12 , comprising an epoxy cap layer on the back of the package substrate encapsulating the planar inductor. 
     
     
         18 . The device as in  claim 12 , wherein the planar inductor comprises copper. 
     
     
         19 . The device as in  claim 12 , wherein the device has a thickness of 500 μm-700 μm, and the heat transfer antenna has a width of 5 μm-15 μm and a depth of 50 μm-100 μm. 
     
     
         20 . The device as in  claim 12 , wherein the heat transfer antenna provides shallow trench isolation, whereby the heat transfer antenna reduces electric current leakage between adjacent semiconductor device components.